Methods and apparatus for limiting communication capabilities in mobile communication devices

ABSTRACT

Techniques for use in a mobile device involve detecting a temperature condition at said device and, in response, operating in a limited communication state for which only emergency communication is permitted. When the mobile device receives a user-initiated communication request, the mobile device inhibits non-emergency communication but permits emergency communication despite the existence of said temperature condition.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of and dams priority to U.S.non-provisional patent application having application Ser. No.12/704,052 and filing date of 11 Feb. 2010, now U.S. Pat. No. 8,045,969,which is a continuation of and claims priority to application havingapplication Ser. No. 11/683,283 and filing date of 7 Mar. 2007, now U.S.Pat. No. 7,689,256, which is a continuation of and claims priority toapplication having application Ser. No. 10/704,846 and filing date of 10Nov. 2003, now U.S. Pat. No. 7,206,567, each application being herebyincorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present invention relates generally to mobile communication deviceswhich operate in wireless communication networks, and more particularlyto methods and apparatus for limiting communication capabilities at themobile device based on predetermined conditions detected at the mobiledevice.

2. Description of the Related Art

Modern-day mobile communication devices which operate in wirelesscommunication networks provide end users with the ability to place andreceive two-way voice calls, send and receive text messages and e-mailmessages, and send and receive other information such as Internet data.Such communication devices utilize a radio frequency (RF) transceiverfor transmitting and receiving such information.

Unfortunately, adverse conditions (such as adverse temperatureconditions) may compromise the performance or utility of the mobiledevice. For example, when a mobile device is communicating informationwith use of its RF transceiver, the RF transceiver heats up and itstemperature rises. If the temperature of the RF transceiver is outsidecertain specification parameters, the RF transceiver undesirably emitsspurious signals at unacceptable levels. These spurious signals may beoutside certain standards, such as those established by the FederalCommunications Commission (FCC) or Industry Canada, for example, and/orcause interference with other communications in the network. Inaddition, if the temperature of a rechargeable battery of the mobiledevice is outside certain specification parameters for too long, thebattery may experience permanent damage and require replacement or couldeven explode.

Under such adverse conditions, the mobile station could power down itscircuitry and inhibit all communications, but the end user would be leftwith no ability to communicate information. This would be undesirable inat least some circumstances, such as in emergency situations. What areneeded are methods and apparatus which overcome the deficiencies ofcurrent practices.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of present invention will now be described by way of examplewith reference to attached figures, wherein:

FIG. 1 is a block diagram which illustrates pertinent components of amobile communication device which communicates within a wirelesscommunication network;

FIG. 2 is a more detailed diagram of a preferred mobile communicationdevice of FIG. 1;

FIG. 3 is a state diagram showing various communicating states of themobile communication device of FIGS. 1 and 2; and

FIG. 4 is a flowchart for describing a method of limiting communicationcapabilities in the mobile communication device of FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a block diagram of a communication system 100 which includes amobile station 102 which communicates through a wireless communicationnetwork 104. Mobile station 102 preferably includes a visual display112, a keyboard 114, and perhaps one or more auxiliary user interfaces(UI) 116, each of which is coupled to a controller 106. Controller 106is also coupled to radio frequency (RF) transceiver circuitry 108 and anantenna 110.

Typically, controller 106 is embodied as a central processing unit (CPU)which runs operating system software in a memory component (not shown).Controller 106 will normally control overall operation of mobile station102, whereas signal processing operations associated with communicationfunctions are typically performed in RF transceiver circuitry 108.Controller 106 interfaces with device display 112 to display receivedinformation, stored information, user inputs, and the like. Keyboard114, which may be a telephone type keypad or full alphanumeric keyboard,is normally provided for entering data for storage in mobile station102, information for transmission to network 104, a telephone number toplace a telephone call, commands to be executed on mobile station 102,and possibly other or different user inputs.

Mobile station 102 sends communication signals to and receivescommunication signals from network 104 over a wireless link via antenna110. RF transceiver circuitry 108 performs functions similar to those ofa radio network (RN) 128, including for example modulation/demodulationand possibly encoding/decoding and encryption/decryption. It is alsocontemplated that RF transceiver circuitry 108 may perform certainfunctions in addition to those performed by RN 128. It will be apparentto those skilled in art that RF transceiver circuitry 108 will beadapted to particular wireless network or networks in which mobilestation 102 is intended to operate.

Mobile station 102 may consist of a single unit, such as a datacommunication device, a cellular telephone, a multiple-functioncommunication device with data and voice communication capabilities, apersonal digital assistant (PDA) enabled for wireless communication, ora computer incorporating an internal modem. Alternatively, mobilestation 102 may be a multiple-module unit comprising a plurality ofseparate components, including but in no way limited to a computer orother device connected to a wireless modem. In particular, for example,in the mobile station block diagram of FIG. 1, RF transceiver circuitry108 and antenna 110 may be implemented as a radio modem unit that may beinserted into a port on a laptop computer. In this case, the laptopcomputer would include display 112, keyboard 114, one or more auxiliaryUIs 116, and controller 106 embodied as the computer's CPU. It is alsocontemplated that a computer or other equipment not normally capable ofwireless communication may be adapted to connect to and effectivelyassume control of RF transceiver circuitry 108 and antenna 110 of asingle-unit device such as one of those described above. Such a mobilestation 102 may have a more particular implementation as described laterin relation to mobile station 202 of FIG. 2.

Mobile station 102 includes a battery interface 122 for receiving one ormore rechargeable batteries 124 or a battery pack. Battery 124 provideselectrical power to electrical circuitry in mobile station 102, andbattery interface 122 provides for a mechanical and electricalconnection for battery 124. Battery interface 122 is coupled to aregulator 126 which regulates power to the device. Mobile station 102also operates using a memory module 120, such as a Subscriber IdentityModule (SIM) or a Removable User Identity Module (R-UIM), which isconnected to or inserted in mobile station 102 at an interface 118. Asan alternative to a SIM or an R-UIM, mobile station 102 may operatebased on configuration data programmed by a service provider into amemory module within controller 106 which is a non-volatile memory.

Mobile station 102 also includes one or more temperature sensors and abattery voltage sensor 154 which are used to control its operationalstates and communication capabilities (described later in detail inrelation to FIGS. 3-4). In the present embodiment, two temperaturesensors are included in mobile station 102. One temperature sensor 150is located adjacent RF transceiver 108 and, more specifically, adjacentto a power amplifier (PA) of RF transceiver 108. Temperature sensor 150is coupled to controller 106 which continually monitors a temperaturefrom temperature sensor 150. Temperature sensor 150 may be, for example,a thermistor having a resistance which varies in accordance withtemperature changes which are detected as voltage changes at controller106. When mobile station 102 is communicating information with use of RFtransceiver 108 (e.g. with its transmitter on), for example, RFtransceiver 108 heats up and its temperature rises. The ambienttemperature also affects the operating temperature of RF transceiver108. If the temperature of RF transceiver 108 is outside certainspecification parameters, spurious signals would be undesirably emittedat unacceptable levels. However, mobile station 102 operates toeliminate or reduce the possibility of such occurrences as will bedescribed later below in relation to FIGS. 3 and 4.

Note that, although only a single temperature sensor 150 is shown anddescribed for RF transceiver 108, a temperature sensor may be utilizedfor each one of multiple PAs in mobile station 102 which correspond tomultiple frequency bands within which the mobile station 102 may operate(e.g. cellular band, PCS band, etc.).

Another temperature sensor 152 may be located in battery or battery pack124. Temperature sensor 152 is coupled to controller 106 through batteryinterface 122. Temperature sensor 152 may be, for example, a thermistorwhich fluctuates its resistance in accordance with changes intemperature to provide a change in voltage which is detected atcontroller 106. When mobile station 102 is communicating informationwith use of RF transceiver 108 (e.g. with its transmitter on), forexample, battery 124 heats up and its temperature rises. The ambienttemperature also affects the temperature of battery 124. If thetemperature of battery 124 is outside certain specification parametersfor too long of a time period, battery 124 may experience permanentdamage and require replacement or could even explode. However, mobilestation 102 operates to eliminate or reduce the possibility of suchoccurrences as will be described later below in relation to FIGS. 3 and4.

Battery voltage sensor 154 is also coupled to controller 106 throughbattery interface 122. Battery voltage sensor 154 may be implementedusing an analog-to-digital (A/D) converter, for example. Battery voltagesensor 154 is used to continually measure the voltage of battery 256, sothat controller 106 may appropriately control RF transceiver 108. Inparticular, when the battery voltage becomes low, mobile station 102operates to limit the use of RF transceiver 108 to extend the life ofbattery 124 as will be described later below.

Mobile station 102 communicates in and through wireless communicationnetwork 104. In the embodiment of FIG. 1, wireless network 104 is aThird Generation (3G) supported network based on Code Division MultipleAccess (CDMA) technologies. In particular, wireless network 104 is acdma2000™ network which includes fixed network components coupled asshown in FIG. 1. Coma2000™ is a trademark of the TelecommunicationsIndustry Association (TIA). Wireless network 104 of the cdma2000™ typeincludes a Radio Network (RN) 128, a Mobile Switching Center (MSC) 130,a Signaling System 7 (SS7) network 140, a Home LocationRegister/Authentication Center (HLR/AC) 138, a Packet Data Serving Node(PDSN) 132, an IP network 134, and a Remote Authentication Dial-In UserService (RADIUS) server 136. SS7 network 140 is communicatively coupledto a network 142 (such as a Public Switched Telephone Network or PSTN),whereas IP network is communicatively coupled to a network 144 (such asthe Internet).

During operation, mobile station 102 communicates with RN 128 whichperforms functions such as call-setup, call processing, and mobilitymanagement. RN 128 includes a plurality of base station transceiversystems that provide wireless network coverage for a particular coveragearea commonly referred to as a “cell”. A given base station transceiversystem of RN 128, such as the one shown in FIG. 1, transmitscommunication signals to and receives communication signals from mobilestations within its cell. The base station transceiver system normallyperforms such functions as modulation and possibly encoding and/orencryption of signals to be transmitted to the mobile station inaccordance with particular, usually predetermined, communicationprotocols and parameters, under control of its controller. The basestation transceiver system similarly demodulates and possibly decodesand decrypts, if necessary, any communication signals received frommobile station 102 within its cell. Communication protocols andparameters may vary between different networks. For example, one networkmay employ a different modulation scheme and operate at differentfrequencies than other networks. The underlying services may also differbased on its particular protocol revision.

The wireless link shown in communication system 100 of FIG. 1 representsone or more different channels, typically different radio frequency (RF)channels, and associated protocols used between wireless network 104 andmobile station 102. An RF channel is a limited resource that must beconserved, typically due to limits in overall bandwidth and a limitedbattery power of mobile station 102. Those skilled in art willappreciate that a wireless network in actual practice may includehundreds of cells depending upon desired overall expanse of networkcoverage. All pertinent components may be connected by multiple switchesand routers (not shown), controlled by multiple network controllers.

For all mobile station's 102 registered with a network operator,permanent data (such as mobile station 102 user's profile) as well astemporary data (such as mobile station's 102 current location) arestored in a HLR/AC 138. In case of a voice call to mobile station 102,HLR/AC 138 is queried to determine the current location of mobilestation 102. A Visitor Location Register (VLR) of MSC 130 is responsiblefor a group of location areas and stores the data of those mobilestations that are currently in its area of responsibility. This includesparts of the permanent mobile station data that have been transmittedfrom HLR/AC 138 to the VLR for faster access. However, the VLR of MSC130 may also assign and store local data, such as temporaryidentifications. Mobile station 102 is also authenticated on systemaccess by HLR/AC 138. In order to provide packet data services to mobilestation 102 in a cdma2000™ based network, RN 128 communicates with PDSN132. PDSN 132 provides access to the Internet 144 (or intranets,Wireless Application Protocol (WAP) servers, etc.) through IP network134. PDSN 132 also provides foreign agent (FA) functionality in mobileIP networks as well as packet transport for virtual private networking.PDSN 132 has a range of IP addresses and performs IP address management,session maintenance, and optional caching. RADIUS server 136 isresponsible for performing functions related to authentication,authorization, and accounting (AAA) of packet data services, and may bereferred to as an AAA server.

Those skilled in art will appreciate that wireless network 104 may beconnected to other systems, possibly including other networks, notexplicitly shown in FIG. 1. A network will normally be transmitting atvery least some sort of paging and system information on an ongoingbasis, even if there is no actual packet data exchanged. Although thenetwork consists of many parts, these parts all work together to resultin certain behaviours at the wireless link. We use a cdma2000™ networkas an example for the description, but these techniques in the presentapplication are not limited to the use of cdma2000™.

FIG. 2 is a detailed block diagram of a preferred mobile station 202.Mobile station 202 is preferably a two-way communication device havingat least voice and advanced data communication capabilities, includingthe capability to communicate with other computer systems. Depending onthe functionality provided by mobile station 202, it may be referred toas a data messaging device, a two-way pager, a cellular telephone withdata messaging capabilities, a wireless Internet appliance, or a datacommunication device (with or without telephony capabilities). Mobilestation 202 may communicate with any one of a plurality of base stationtransceiver systems 200 within its geographic coverage area.

Mobile station 202 will normally incorporate a communication subsystem211, which includes a receiver 212, a transmitter 214, and associatedcomponents, such as one or more (preferably embedded or internal)antenna elements 216 and 218, local oscillators (LOs) 213, and aprocessing module such as a digital signal processor (DSP) 220.Communication subsystem 211 is analogous to RF transceiver circuitry 108and antenna 110 shown in FIG. 1. As will be apparent to those skilled infield of communications, particular design of communication subsystem211 depends on the communication network in which mobile station 202 isintended to operate.

Mobile station 202 may send and receive communication signals over thenetwork after required network registration or activation procedureshave been completed. Signals received by antenna 216 through the networkare input to receiver 212, which may perform such common receiverfunctions as signal amplification, frequency down conversion, filtering,channel selection, and like, and in example shown in FIG. 2,analog-to-digital (A/D) conversion. A/D conversion of a received signalallows more complex communication functions such as demodulation anddecoding to be performed in DSP 220. In a similar manner, signals to betransmitted are processed, including modulation and encoding, forexample, by DSP 220. These DSP-processed signals are input totransmitter 214 for digital-to-analog (D/A) conversion, frequency upconversion, filtering, amplification and transmission over communicationnetwork via antenna 218. DSP 220 not only processes communicationsignals, but also provides for receiver and transmitter control. Forexample, the gains applied to communication signals in receiver 212 andtransmitter 214 may be adaptively controlled through automatic gaincontrol algorithms implemented in DSP 220.

Network access is associated with a subscriber or user of mobile station202, and therefore mobile station 202 requires a memory module 262, suchas a Subscriber Identity Module or “SIM” card or a Removable UserIdentity Module (R-UIM), to be inserted in or connected to an interface264 of mobile station 202 in order to operate in the network.Alternatively, flash memory 224 may be a non-volatile memory which isprogrammed with configuration data by a service provider so that mobilestation 202 may operate in the network. Since mobile station 202 is amobile battery-powered device, it also includes a battery interface 254for receiving one or more rechargeable batteries 256. Such a battery 256provides electrical power to most if not all electrical circuitry inmobile station 202, and battery interface 254 provides for a mechanicaland electrical connection for it. The battery interface 254 is coupledto a regulator (not shown in FIG. 2) which provides power V+ to all ofthe circuitry.

Mobile station 202 includes a microprocessor 238 (which is oneimplementation of controller 106 of FIG. 1) which controls overalloperation of mobile station 202. This control includes network selectiontechniques of the present application. Communication functions,including at least data and voice communications, are performed throughcommunication subsystem 211. Microprocessor 238 also interacts withadditional device subsystems such as a display 222, a flash memory 224,a random access memory (RAM) 226, auxiliary input/output (I/O)subsystems 228, an external communication port 230, a keyboard 232, aspeaker 234, a microphone 236, a short-range communications subsystem240, and any other device subsystems generally designated at 242. Someof the subsystems shown in FIG. 2 perform communication-relatedfunctions, whereas other subsystems may provide “resident” or on-devicefunctions. Notably, some subsystems, such as keyboard 232 and display222, for example, may be used for both communication-related functions,such as entering a text message for transmission over a communicationnetwork, and device-resident functions such as a calculator or tasklist. Operating system software used by microprocessor 238 is preferablystored in a persistent store such as flash memory 224, which mayalternatively be a read-only memory (ROM) or similar storage element(not shown). Those skilled in the art will appreciate that the operatingsystem, specific device applications, or parts thereof, may betemporarily loaded into a volatile store such as RAM 226.

Microprocessor 238, in addition to its operating system functions,preferably enables execution of software applications on mobile station202. A predetermined set of applications which control basic deviceoperations, including at least data and voice communicationapplications, will normally be installed on mobile station 202 duringits manufacture. A preferred application that may be loaded onto mobilestation 202 may be a personal information manager (PIM) applicationhaving the ability to organize and manage data items relating to usersuch as, but not limited to, e-mail, calendar events, voice mails,appointments, and task items. Naturally, one or more memory stores areavailable on mobile station 202 and SIM 262 to facilitate storage of PIMdata items and other information.

The PIM application preferably has the ability to send and receive dataitems via the wireless network. In a preferred embodiment, PIM dataitems are seamlessly integrated, synchronized, and updated via thewireless network, with the mobile station user's corresponding dataitems stored and/or associated with a host computer system therebycreating a mirrored host computer on mobile station 202 with respect tosuch items. This is especially advantageous where the host computersystem is the mobile station user's office computer system. Additionalapplications may also be loaded onto mobile station 202 through network,an auxiliary I/O subsystem 228, communication port 230, short-rangecommunications subsystem 240, or any other suitable subsystem 242, andinstalled by a user in RAM 226 or preferably a non-volatile store (notshown) for execution by microprocessor 238. Such flexibility inapplication installation increases the functionality of mobile station202 and may provide enhanced on-device functions, communication-relatedfunctions, or both. For example, secure communication applications mayenable electronic commerce functions and other such financialtransactions to be performed using mobile station 202.

In a data communication mode, a received signal such as a text message,an e-mail message, or web page download will be processed bycommunication subsystem 211 and input to microprocessor 238.Microprocessor 238 will preferably further process the signal for outputto display 222 or alternatively to auxiliary I/O device 228. A user ofmobile station 202 may also compose data items, such as e-mail messages,for example, using keyboard 232 in conjunction with display 222 andpossibly auxiliary I/O device 228. Keyboard 232 is preferably a completealphanumeric keyboard and/or telephone-type keypad. These composed itemsmay be transmitted over a communication network through communicationsubsystem 211.

For voice communications, the overall operation of mobile station 202 issubstantially similar, except that the received signals would be outputto speaker 234 and signals for transmission would be generated bymicrophone 236. Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on mobilestation 202. Although voice or audio signal output is preferablyaccomplished primarily through speaker 234, display 222 may also be usedto provide an indication of the identity of a calling party, duration ofa voice call, or other voice call related information, as some examples.

Communication port 230 in FIG. 2 is normally implemented in a personaldigital assistant (PDA)-type communication device for whichsynchronization with a user's desktop or laptop computer is a desirable,albeit optional, component. Examples of such a port include an RS-232port and a Universal Serial Bus (USB). Communication port 230 enables auser to set preferences through an external device or softwareapplication and extends the capabilities of mobile station 202 byproviding for information or software downloads to mobile station 202other than through a wireless communication network. The alternatedownload path may, for example, be used to load an encryption key ontomobile station 202 through a direct and thus reliable and trustedconnection to thereby provide secure device communication.

Short-range communications subsystem 240 of FIG. 2 is an additionaloptional component which provides for communication between mobilestation 202 and different systems or devices, which need not necessarilybe similar devices. For example, subsystem 240 may include an IrDA™communication module or a Bluetooth™ communication module to provide forcommunication with similarly-enabled systems and devices. IrDA™ andBluetooth™ are trademarks of Infrared Data Association and Bluetooth SIGInc., respectively. A PDA-type communication device may also use IrDA orBluetooth technology for synchronization with a user's desktop or laptopcomputer.

Mobile station 202 also includes one or more temperature sensors and abattery voltage sensor 290 which are used to control its operationalstates and communication capabilities (described later in detail inrelation to FIGS. 3-4). In the present embodiment, two temperaturesensors are included in mobile station 202. One temperature sensor 280is located adjacent communication subsystem 211 and, more specifically,adjacent to a power amplifier (PA) of communication subsystem 211, forexample. Temperature sensor 280 is coupled to microprocessor 238, whichcontinually monitors a temperature from temperature sensor 280.Temperature sensor 280 may be, for example, a thermistor having aresistance which varies in accordance with changes in temperature toprovide a change in voltage detected at microprocessor 238. When mobilestation 202 is communicating information with use of communicationsubsystem 211 (e.g. with its transmitter 214 on), for example,communication subsystem 211 heats up and its temperature rises. Theambient temperature also affects the temperature of components incommunication subsystem 211. If the temperature of communicationsubsystem 211 is outside certain specification parameters, spurioussignals would be undesirably emitted by transmitter 214 at unacceptablelevels. However, mobile station 202 operates to eliminate or reduce thepossibility of such occurrences as will be described later below inrelation to FIGS. 3 and 4.

Note that, although only a single temperature sensor 280 is shown anddescribed for communication subsystem 211, a temperature sensor may beutilized for each one of multiple PAs in mobile station 202 whichcorrespond to multiple frequency bands within which the mobile station202 may operate (e.g. cellular band, PCS band, etc.).

Another temperature sensor 282 is located in battery or battery pack256. Temperature sensor 282 is coupled to microprocessor 238 throughbattery interface 254. Temperature sensor 282 may be, for example, athermistor which fluctuates its resistance in accordance with changes intemperature to provide a change in voltage detected at microprocessor238. When mobile station 202 is communicating information with use ofcommunication subsystem 211 (e.g. with its transmitter 214 on), forexample, battery 256 heats up and its temperature rises. The ambienttemperature also affects the temperature of battery 256. If thetemperature of battery 256 is outside certain specification parametersfor too long of a time period, battery 256 may experience permanentdamage and require replacement or could even explode. However, mobilestation 202 operates to eliminate or reduce the possibility of suchoccurrences as will be described later below in relation to FIGS. 3 and4.

Battery voltage sensor 290 is also coupled to microprocessor 238 throughbattery interface 254. Battery voltage sensor 290 may be implementedusing an analog-to-digital (A/D) converter, for example. Battery voltagesensor 290 is used to continually measure the voltage of battery 256, sothat microprocessor 238 may appropriately control communicationsubsystem 211. In particular, when the battery voltage becomes low,mobile station 202 operates to limit the use of communication subsystem211 to extend the life of battery 256 as will be described later below.

FIG. 3 is a state diagram 300 which illustrates various operating statesof a mobile communication device such as the mobile station shown anddescribed in relation to FIGS. 1 and 2. More particularly, state diagram300 illustrates various communication states which are responsive todifferent operating conditions of the mobile station. In the presentembodiment of FIG. 3, the different communication states of the mobilestation are responsive to different temperature conditions of the mobilestation. The changes in communication states, however, could beresponsive to other changing operating conditions of the mobile station,such as low battery conditions or automatic location-based power downconditions (e.g. automatic airplane power down).

As shown in state diagram 300, the communication states of the mobilestation include a full communication state 302, a limited communicationstate 304, an emergency-only text communication state 306, and an offstate 308. In general, the mobile station continually monitors a readingfrom a sensor and selects one of the communication states 302, 304, 306,and 308 based on the reading. In particular in FIG. 3, the mobilestation monitors an operating temperature T based on a reading from atemperature sensor and selects one of the communication states 302, 304,306, and 308 based on temperature. Several predetermined temperaturethresholds are known by and stored in memory of the mobile station. Inthis exemplary embodiment, six (6) different temperature thresholds T1,T2, T3, T4, T5, and T6 are known by and stored in the mobile station,where T1<T2<T3<T4<T5<T6. These six different temperature thresholds areassociated with different operating temperature ranges which may includea normal operating temperature range T3-T4; one or more poor operatingtemperature ranges T2-T3 and T4-T5 (lower and upper, respectively); oneor more very poor operating temperature ranges T1-T2 and T5-T6 (lowerand upper, respectively); and one or more extremely poor operatingtemperature ranges less than T1 or greater than T6.

Preferably, the mobile station selects one of the communication states302, 304, 306, and 308 based on readings from more than one sensor. Forexample, the mobile station may select one of the communication statesbased on both the temperature of the RF PA and the temperature of thebattery. As another example, the mobile station may select one of thecommunication states based on both the temperature of the RF PA and thebattery voltage of the battery. Using this type of approach, each sensorhas a corresponding set of predetermined thresholds which are stored inmemory of the mobile station. Accordingly, a communication state of themobile station is determined and selected based on readings anddecisions from all of relevant sensors. For example, the mobile stationmay select the most limiting communication state associated with any oneof the sensors as the current communication state.

For clarity, state diagram 300 of FIG. 3 will be described where asingle operating temperature (which may be viewed as a composite readingfrom all sensors) drives the selection of a communication state. Undernormal operating circumstances, the mobile station identifies theoperating temperature T to be within a predetermined temperature rangeof T3≦T≦T4. T3 may be about −10° C. and T4 may be about 60° C., forexample. In this case, the mobile station will operate in fullcommunication state 302. In full communication state 302, the mobilestation allows its full communication capabilities for the end user. Themobile station permits two-way voice calls and data packet communicationsessions (e.g. e-mail message and Internet data communications). Thewireless transceiver of the mobile station is kept operational, althoughthe transmitter and receiver may be powered down intermittently in sleepmodes when necessary to conserve power as is conventional. The codingand modulation methods utilized by the wireless transceiver are notlimited in any way in state 302. Preferably, a visual indication of thiscommunication state is provided in the visual display of the mobilestation (e.g. “FULL”).

In poor temperature conditions, the mobile station identifies theoperating temperature T to be within one of the poor operatingtemperature ranges, where T2≦T<T3 or T4<T≦T5. T2 may be about −20° C.and T5 may be about 80° C., for example. If the operating temperature Tis poor, spurious signals may be undesirably emitted by the transmitterat unacceptable levels when transmitting at the allowed maximum transmitpower level in normal operating circumstances. Also, the battery mayexperience permanent damage and require replacement. Thus, if T2≦T<T3 orT4<T≦T5, the mobile station controls itself to operate in limitedcommunication state 304. In limited communication state 304, the mobilestation allows only limited communication capabilities for the end user.The transmitter is normally powered off while the receiver is keptoperational (albeit powered down intermittently in sleep modes toconserve power as is conventional). Alternatively, the transmitter andreceiver are both powered off. In limited communication state 304, themobile station does not permit any non-emergency communications such asnon-emergency voice calls, non-emergency data service (e.g.communicating any normal e-mail message, Internet browsing, etc.), andover-the-air service provisioning.

In limited communication state 304, however, the mobile station doespermit the placement of emergency two-way voice calls (e.g. 911 voicecall) and permits any emergency data packet communication (e.g.emergency message or Internet data communication). If an emergencycommunication request is received at the user interface, the transmitter(and receiver where applicable) is powered on and the maximum transmitpower is limited to a lower power level to reduce the likelihood ofunacceptable spurious emissions. Also, the coding and modulation methodsof the wireless transceiver may be limited for the same reasons.Preferably, after a mobile-initiated emergency communication, the mobilestation invokes an emergency callback period during which mobile stationenables and allows network-initiated position location services as wellas incoming voice calls. Typically, a mobile station enters an emergencycallback period lasting for five (5) minutes after an emergency call isterminated. This allows a Public Safety Answer Point (PSAP) the abilityto call back and/or locate the user with use of technology such asAssisted Global Positioning System (A-GPS). Preferably, a visualindication of this communication state is provided in the visual displayof the mobile station (e.g. “LIMITED” or “EMERGENCY ONLY”).

Under more adverse temperature conditions, the mobile station identifiesthe operating temperature T to be within one of the very poor operatingtemperature ranges, where T1≦T<T2 or T5<T≦T6. T1 may be about −25° C.and T6 may be about 100° C., for example. If the operating temperature Tis at such a level, spurious signals may be undesirably emitted by thetransmitter at unacceptable levels when transmitting at the allowedmaximum transmit power level in normal operating circumstances. Also,the battery may experience permanent damage and require replacement.Furthermore, the receiver performance may be degraded. Thus, if T1≦T<T2or T5<T≦T6, the mobile station controls itself to operate inemergency-only text communication state 306. In emergency-only textcommunication state 306, the transmitter and the receiver are keptpowered down (i.e. completely powered off, not merely in a sleep mode ofoperation). The mobile station does not permit any services includingnon-emergency or emergency (e.g. 911) two-way voice calls, ornon-emergency data packet transmissions for end-user communication (e.g.ordinary e-mail message and Internet data communications), andover-the-air service provisioning. The mobile station also does notpermit the reception of ordinary data packet communications (e.g.ordinary e-mail messages). In emergency-only text communication state306, the mobile station only permits a mobile-initiated communication oftext-based emergency messages. Preferably, a visual indication of thiscommunication state may be provided in the visual display of the mobilestation (e.g. “EMERGENCY ONLY TEXT”), assuming that the visual displaycan operate under such conditions.

These emergency text messages may be in the form of a short messageservice (SMS) message and/or an e-mail message, for example, which arecommunicated to some form of a Public-Safety Answering Point (PSAP)supporting messages. Preferably, the text-based emergency message is apredefined, prestored emergency text message in the mobile station (e.g.“EMERGENCY—PLEASE HELP”). In general, the sending of the emergency textmessage is the only time that the transceiver is powered on in state306. The maximum transmit power is preferably limited at an even lowerlevel to reduce the likelihood that no unacceptable spurious emissionsexist. Also preferably, the emergency message is transmitted at a lowdata rate which requests a lower transmit power to achieve a givenreliability of communication. Further, the coding and modulation methodsof the wireless transceiver may be limited if necessary. The informationmay be sent over a control channel (e.g. an access channel) whicheliminates the need of setting up a traffic channel. For example, theemergency text message may be in the form of an emergency SMS messagetransmitted over an access channel. The emergency message may or may notbe accompanied by user-identifying information and/or locationinformation (e.g. pilot phase information). Preferably, such informationis included in the emergency message. An audible indication may beprovided at the user interface to confirm that the emergency textmessage has been successfully transmitted and/or received (especiallyimportant where the visual display of the mobile station may not beoperable under such conditions).

Under even more adverse operating conditions, the mobile stationidentifies the operating temperature T to be below temperature T1 orabove temperature T6. If the operating temperature T is at such a level,spurious signals may be undesirably emitted by the transmitter atunacceptable levels or the battery may experience permanent damage andrequire replacement or could even explode. In this case, the mobilestation controls itself to power down to the off state 308. In off state308, the mobile station is completely shut down and no communicationcapabilities are provided for the end user. Not even emergencycommunications can be provided by the mobile station in off state 308.

Thus, when a communication request for communicating information isreceived through a user interface (e.g. keypad, keyboard, or touchscreen display) of the mobile station, the mobile station will inhibitor allow the communication request depending on which communicationstate it is operating in. In the limited communication state, forexample, the mobile station will inhibit a non-emergency communicationbut allow an emergency communication.

FIG. 4 is a flowchart which describes a method of limiting communicationcapabilities in a mobile communication device such as the mobile stationdescribed in relation to FIGS. 1 and 2. The communication states andtemperatures/temperature ranges correspond to those described inrelation to state diagram 300 of FIG. 3. A computer program product mayinclude computer instructions stored on a computer storage medium(memory of the mobile station, a floppy disk or CD-ROM) which arewritten in accordance with the described logic.

Beginning at a start block 402 of FIG. 4, the mobile station detectswhether its operating temperature T is within temperature range T3-T4(step 404). If so, the mobile station operates in its full communicationstate (step 406). If the operating temperature T is not withintemperature range T3-T4, the mobile station detects whether theoperating temperature T is within temperature range T2-T3 or T4-T5 (step408). If so, the mobile station operates in its limited communicationstate (step 410). If the operating temperature T is not withintemperature range T2-T3 or T4-T5, the mobile station detects whether itsoperating temperature T is within temperature range T1-T2 or T5-T6 (step412). If so, the mobile station operates in its emergency-onlycommunication state (step 414). If the operating temperature T is notwithin T1-T2 or T5-T6, the mobile station detects whether its operatingtemperature T is less than T1 or greater than T6 (step 416). If so, themobile station powers itself down completely (step 418). The mobilestation will remain powered down from step 418 until the end user powersit back up and the adverse condition is gone. Upon power up, the mobilestation starts again at start block 402 and may operate to follow theprevious decision to obtain the device state. For example, if the mobilestation is determined to be in OFF state again, the mobile stationpowers itself off after an audible or visual indication to the user; ifthe adverse condition is gone, however, the mobile station will remainin a different state corresponding to current conditions.

Although FIGS. 3 and 4 are primarily directed to limiting communicationcapabilities based on temperature, the techniques apply to limitingcommunication capabilities based on low battery voltage in the same way(or limiting communication capabilities based on the combined use oftemperature(s) and low battery voltage).

Final Comments. Methods and apparatus for limiting communicationcapabilities in mobile communication devices have been described. In oneillustrative example, a predetermined condition such as anunsatisfactory temperature or a low battery voltage is detected at themobile communication device. At this time, a communication request forcommunicating information through a wireless communication network isreceived through a user interface. If the communication request is for anon-emergency communication, the non-emergency communication isinhibited during the existence of the predetermined condition. If thecommunication request is for an emergency communication, however, theemergency communication is allowed despite the existence of thepredetermined condition. The emergency communication may be a “911”voice call or an emergency message. The maximum allowed transmit powermay be limited to a certain level to reduce the likelihood thatunacceptable spurious emissions exist. The coding and modulation methodsmay also be limited to a subset of that which the mobile station wouldotherwise support.

The above-described embodiments of the present application are intendedto be examples only. Those of skill in the art may effect alterations,modifications and variations to the particular embodiments withoutdeparting from the scope of the application. For example, instead ofusing temperature-based conditions, low battery conditions or automaticlocation-based power down conditions (e.g. automatic airplane powerdown) may be utilized. The invention described herein in the recitedclaims intends to cover and embrace all suitable changes in technology.

1. A method for use in a mobile device, the method comprising: detectinga temperature condition at said device; in response, operating in alimited communication state for which only emergency communication ispermitted; and operating in a full communication state if saidtemperature condition fails to exist; wherein operating in said fullcommunication state comprises allowing user-initiated communicationrequests for emergency and non-emergency communications from said mobiledevice.
 2. The method of claim 1 wherein an indication of said limitedcommunication state is provided on a visual display.
 3. The method ofclaim 1, further comprising: receiving a user-initiated communicationrequest for an emergency communication; and permitting said emergencycommunication despite the existence of said temperature condition. 4.The method of claim 1, wherein said emergency communication comprises anemergency telephone call.
 5. The method of claim 1, wherein saidemergency communication comprises an emergency data message.
 6. Themethod of claim 1, wherein said emergency communication comprises atleast one of a communication with a public safety access point and acommunication initiated by entry of an emergency telephone number. 7.The method of claim 1, wherein detecting that said temperature conditionexists further comprises: monitoring a temperature based on signals readfrom a temperature sensor; and detecting that said temperature conditionexists based on said monitored temperature.
 8. The method of claim 1,wherein detecting that said temperature condition exists furthercomprises: monitoring a temperature from signals read from a temperaturesensor; and detecting that said temperature condition exists if saidmonitored temperature is greater than a threshold.
 9. The method ofclaim 1, wherein detecting whether said temperature condition existscomprises detecting whether a temperature condition exists in a batteryof said mobile device.
 10. The method of claim 1, wherein detectingwhether said temperature condition exists comprises detecting whether atemperature condition exists at a power amplifier of said mobile device.11. A mobile device configured to provide communications in a wirelesscommunication network, said mobile device comprising: a temperaturesensor; a radio frequency (RF) transceiver configured for wirelesscommunications via said wireless communication network; a processorcoupled to said temperature sensor and said RF transceiver, saidprocessor being configured to: detect a temperature condition at saiddevice based on signals read from said temperature sensor; in response,operate in a limited communication state for which only emergencycommunication is permitted; and operate in a full communication state ifsaid temperature condition fails to exist; wherein operating in saidfull communication state comprises allowing user-initiated communicationrequests for emergency and non-emergency communications from said mobiledevice.
 12. The mobile device of claim 11, further comprising a visualdisplay; wherein said processor is further configured to provide anindication of said limited communication state on said visual display.13. The mobile device of claim 11, further comprising: a batteryinterface configured to receive a battery that provides electrical powerto said RF transceiver and said processor, wherein detecting whethersaid temperature condition exists comprises detecting whether atemperature condition exists at said battery.
 14. The mobile device ofclaim 13, further comprising: said battery, wherein said temperaturesensor is in said battery.
 15. The mobile device of claim 11, whereinsaid temperature sensor comprises a thermistor.
 16. The mobile device ofclaim 11, wherein said mobile device comprises a cellular telephone. 17.The mobile device of claim 11, further comprising a user interface, saiduser interface configured to receive a user-initiated communicationrequest.
 18. The mobile device of claim 17, wherein said user interfacecomprises one of a keypad, a keyboard, and a touch screen display. 19.The mobile device of claim 11, wherein said emergency communicationcomprises at least one of an emergency telephone call and an emergencydata message.
 20. A method for use in a mobile device having a visualdisplay, the method comprising: detecting whether a temperaturecondition exists at said mobile device; and when said temperaturecondition exists, providing a visual indication indicating that saidmobile device is in a limited communication state; wherein said limitedcommunication state comprises a state in which a user-initiatedcommunication request for a non-emergency communication is not permittedand a user-initiated communication request for an emergencycommunication is permitted.
 21. The method of claim 20, furthercomprising: in response to detecting that said temperature conditionexists, operating said mobile device in said limited communicationstate.
 22. The method of claim 20, wherein said visual indicationcomprises an “EMERGENCY ONLY” indication.
 23. The method of claim 20,wherein said non-emergency communication comprises a non-emergencytelephone call and said emergency communication comprises an emergencytelephone call.
 24. The method of claim 20, further comprising: whensaid temperature condition fails to exist, operating in a fullcommunication state; wherein said full communication state comprises astate in which user-initiated communication requests for emergency andnon-emergency telephone calls are permitted.
 25. A method for use in amobile device, the method comprising: detecting a temperature conditionat said device; and in response, operating in a limited communicationstate for which only emergency communication with a public safetyanswering point is permitted.
 26. The method of claim 25, wherein saidemergency communication comprises at least one of an emergency telephonecall and an emergency data message.
 27. The method of claim 25, whereinsaid device comprises a mobile telephone device operative forcommunications in a wireless communication network.
 28. The method ofclaim 25, further comprising: operating in a full communication state ifsaid temperature condition fails to exist; wherein operating in saidfull communication state comprises allowing user-initiated communicationrequests for emergency and non-emergency communications from said mobiledevice.